Tri-Delta only counts daughters and sisters as Tri-Delt legacies. A step-daughter counts if the step-mother wants it to.
I just finished reading my friend's Trident and they had a little article on it. If your aunt gets the Trident have her check out the last page of the most recent one. That'll give a good explanation of legacies.
A niece definitely doesn't count as a Tri-Delt legacy and neither would a "step-niece".
Like twinstars said, every organization is different about what they consider as a legacy. And I'm sure she can write you a great recommendation!
I checked the Panhellenic Council website at USF for you and this is what it said:
"Panhellenic Council rush is held one week before the start of classes in the Fall."
So it seems that you will have to wait until your senior year to rush since you are transferring in Jan. They might have COB, but that would be hard since at many schools it is by invitation only and you wouldn't have met anyone yet. But, keep your ears open in case anyone can go to COB!
Good luck AmyQ!
here's a link to where I got the quote from.
http://ctr.usf.edu/sa/greek.htm